Circuit breaker with latching type auxiliary tripping means



Dec. 22, 1964 K. w. KLEIN ETAL 3,162,740

CIRCUIT BREAKER WITH LATCHING TYPE AUXILIARY TRIPPING MEANS Filed Nov. 9, l962 2 Sheets-Sheet l IN V EN TORS n KEITH \A/. KLEIN,

DAVID B. Powsu.

FIGS BY ATTORNEY 1964 K. w. KLEIN ETAL 3,162,740

CIRCUIT BREAKER WITH LATCHING TYPE AUXILIARY TRIPPING MEANS Filed Nov. 9, 1962 2 Sheets-Sheet 2 INVENTORS FIG'7 KEITH \I\/. KLEIN,

DAVID B. POWELL A TTORNE Y United States Patent 3,162,740 CHRCUIT BREAKER WITH LATCHENG TYRE AUXILKARY TPHNG MEANS Keith W. Klein, Sirnshury, and David B. Powell, Bristol,

Conn, assignors to General Electric Company, a corporation of New York Filed Nov. 9, 1962., Ser. No. 236,603. 7 Claims. (Cl. 2tl@1tl6) The present invention relates to electric circuit breakers, and more particularly to electric circuit breakers of the molded insulating case type including means for causing automatic opening in response to predetermined current conditions therethrough and also means for causing opening in response to other electrical conditions such as a change of the condition of a remote control circuit, or a decrease of line voltage.

Electric circuit breakers of the molded case type commonly include manually operable mechanism for operating contacts thereof between open and closed circuit position, and in addition, current responsive means for causing automatic opening operation of the contacts upon the occurrence of certain predetermined current conditions through the circuit breaker. In a certain num ber of uses of such circuit breakers, it is also desirable that the circuit breaker include means for permitting remote operation of the circuit breaker to the open circuit condition. Likewise, in a certain number of uses, it is desirable that the circuit breaker include means for causing automatic opening of the breaker in response to a change in the voltage conditions of the circuit and particularly in response to a predetermined drop in the voltage of the circuit.

'Accordingly, there have been provided in accordance with prior art a number of accessory devices adapted for use with various molded case circuit breakers to perform these functions. Such devices have, however, been found to be unsuited for use with a circuit breaker of the type shown in the present invention, primarily because of the lack of sufficient space. In addition, prior art devices of this type have required the use of screws or other fastening means to mount them within the circuit breaker, thereby increasing the difficulty of installing such devices, particularly when attempted by the user in the field.

It is an object of the present invention to provide an electric circuit breaker and an undervoltage tripping device usable therewith which is extremely compact and effective.

It is a further object of the invention to provide an electric circuit breaker including an undervoltage tripping device which can be readily installed in the circuit breaker by the user without the use of separate fastens ing means such as screws, and which will nevertheless be accurately and securely positioned in the circuit breaker.

It is a further object of the invention to provide an undervoltage tripping device for use with an electric circuit breaker which can be readily converted to provide a remote-control trip device.

In accordance with the invention in one form, an electric circuit breaker is provided of the multi-pole molded case breaker type, having at least two elongated chambers therein each containing parts providing one currentpath or pole of the circuit breaker, and current respon sive tripping means for causing automatic opening of all poles simultaneously. Undervoltage tripping means is provided including a generally flat sheet metal supporting frame, said frame being adapted to be wedged between the trip unit insulating casing and cooperating abutments carried by the partitions defining the aforesaid 3,162,740 Patented Dec. 22, 1964 pole-chambers, whereby the use of separate fastening means is eliminated.

In accordance with another aspect of the invention, the undervoltage tripping assembly includes an actuating plunger which is normally latched and which upon release is projected into the circuit breaker trip unit, engaging the trip bar and causing automatic opening. Also, in order to facilitate assembly of the undervoltage tripping mechanism, the plunger is provided with a special retracted or latched position in which it may be placed during installation, the parts being disposed and arranged so that during installation, the actuating plunger is automatically released from its special latched position and assumes its normal latched position.

In accordance with a further aspect of the invention, the undervoltage tripping device is usable as a remote control trip device which normally has no voltage applied thereto and is actuated by the application of voltage, simply by shifting the anchor point of a biasing spring and by reversing the direction of action of an actuating solenoid.

The invention will be more fully understood from the following detailed description, and its scope will be pointed out in the appended claims.

In the drawings,

FIGURE 1 is a side elevation view, partially broken away, of a molded case circuit breaker incorporating the invention;

FIGURE 2 is an elevation view, on enlarged scale, of a portion of the circuit breaker of FIGURE 1, showing the undervoltage tripping device and a portion of the trip unit;

FIGURE 3 is a top plan view of a portion of the circuit breaker of FIGURE 1, showing the installed position of the undervoltage release device;

FIGURE 4 is an exploded perspective view of the undervoltage tripping device or FIGURE 2;

FIGURE 5 is a view similar to FIGURE 2, but showing the parts at the instant of release, such as on the occurrence of an undervoltage condition in the circuit, and prior to opening movement of the contact arm;

FIGURE 6 is a view of the undervoltage tripping device of FIGURE 2 shown in the process of installation, and

FIGURE 7 is an elevation view similar to FIGURE 2 showing a modification of the invention adapted to act as a remote control trip device.

In FIGURE 1, the invention is shown as incorporated in an electric circuit breaker including a generally rectangular insulating casing comprising a base 10 and a cover 11. A pair of relatively separable contacts are provided mounted in the base 10 comprising a relatively stationary contact 12 and a relatively movable contact 13. The stationary contact 12 is mounted at one end of a terminal strap 14, the other end of which supports a line terminal connecting member 15. The movable contact member 13 is resiliently carried by a contact arm 16 which is rigidly attached to a contact cross-arm 17 pivotally supported in the base ill by suitable means, not shown.

The movable contact 13 is connected by flexible electrical connector 18 and by connecting strap 19 to an input terminal 20 of a trip unit 21, having a corresponding output terminal 22 supporting a cable connector 23.

The circuit breaker illustrated is a three-pole circuit breaker and comprises three elongated chambers or current paths or poles, each of which contains current carrying parts and contacts similar to those described and illustrated in connected with FIGURE 1.

Operating mechanism is also provided mounted in the base 119 for operating the contact cross-arn1 17 and the associated contact arms of the other pole chambers between open and closed circuit positions, by means of a manually operable handle member 24. The operating mechanism referred to includes a normally restrained but releasable member, not shown, which is adapted to be releasably held by a trip member 27 mounted in suitable latch means, not shown, carried by the trip unit 21 and adapted to be released thereby upon the occurrence of predetermined current conditions. An electric circuit breaker mechanism of the type described is shown, for example, and more fully described, in co-pending application Serial No. 212,432, Klein and Powell, filed July 25, 1962, and assigned to the same assignee as the present invention.

The trip unit 21 includes a separate box-like insulating enclosure comprising a main body portion 21A and a cover portion 21B. The trip unit 21 may be of any suitable type including a member 27 (see FIGURE 2) which is movable to cause releasing or tripping action and release of the releasable member 25. A trip unit of the type described, for example, is shown in application Serial No. 204,730, Klein and Powell, filed June 25, 1962, and assigned to the same assignee as the present invention.

For the purpose of initiating tripping operation of the trip unit 21 upon the occurrence of a predetermined decrease in voltage in a selected circuit, such-for instance as the circuit providing current through the contacts 12, 13, an undervoltage tripping device is provided as shown generally at 30.

Referring particularly to FIGURES 2, 3 and 4, the undervoltage tripping device 30 comprises a generally fiat sheet metal supporting frame 31 having a bent-over end portion 32 at one end and a generally hook-shaped termination 33 at the other end. The frame 31 also includes a transversely extending supporting arm 34 for a purpose to be described.

A solenoid 35 is rigidly mounted on the frame 31 by suitable means such as by screws 36 (see FIGURE 3).

Referring particularly to FIGURE 4, a first supporting post 37 is mounted rigidly to the frame 31 and has a reduced end portion or pin 3%. A tripping plunger 39 of flat sheet metal is also provided, having an elongated slot 40 therein. The plunger 39 is slidably supported on the pin 38 which extends through the slot 40, and the plunger 39 is slidably retained on the pin 38 by a snap-on type retainer 41. The forward end of the plunger 39 extends through an elongated slot 42 in the end portion 32 of the frame 31. The plunger 39 also includes a notch 43 and a bent-over lug portion 44- and a notch 45, for purposes to be described. The plunger 3% is adapted in one position thereof to engage the trip member 27 of the trip unit 21 to move it counterclockwise as viewed in FIGURE 2 to initiate tripping.

For the purpose of moving the plunger 39 to the right to initiate tripping when desired, a link member 46 is provided, which is pivotally supported on a reduced end portion 48A of a second supporting post id. The link 46 carries at one end thereof a pin 47 which has one end portion 47A extending at the back side of the link 46 and a second portion 47B extending toward the front side of the link 46.

When the parts are in assembled relation, as shown in FIGURE 2, the link 46 underlies the plunger member 39, and the end 473 of the pin 47 extends into the notch 43 of the plunger 39. Rotational movement of the link 46 about its pivot 48, therefore causes the pin 47B to engage one end or the other of the notch 43, moving the plunger 39 to the right or to the left as viewed, depending upon the direction of rotation of the link 46.

The link 46 is constantly biased for rotation in a clockwise direction by means of a torsion spring 4?, which has one end thereof hooked around the lower edge of the frame 31 and which has its other end 4913 pressing against the portion 47A of the pin 47.

For the purpose of releasably holding the plunger member 39 against movement to the right under the influence of the spring 49, a latch member 50 is provided. The latch member 50 is also pivotally supported on the reduced upper end portion 48A of the post 48. A spacer member 51 separates the latch member 59 from the link member 46 on the pin 48A. The latch member 50 is retained on the extension 48A by means of a snap ring 52 which engages in a corresponding groove in the pin 48A. The latch member 50 has an enlarged opening 53 generally centrally thereof to provide clearance for the upper end portion 38 of the post 37, in all positions of the latch member 56. The latch member 59 includes a latching surface or shoulder 54- which is adapted to engage and releasably restrain the lug member 44 of the plunger 39. An abutment portion 55 of the latch member 50 serves to limit the amount of latch overlap of the lug 44 on the latch surface 54. The latch 50 is received within a slot 56A in the plunger or actuator 56 of the solenoid 35, and is pivotally connected thereto by means of a cotter pin 5'7. The latch member 50 is constantly biased in a tripping direction by means of the tension spring 58 which is connected at one end in a hole 59 of the latch member Sil and has its other end in hooked engagement with the arm 34 of the frame 31.

Operation In FIGURE 2, the parts are shown in the position which they occupy during normal operation of the circuit breaker. In this condition, the plunger 56 is held in the retracted position by the solenoid 35 which is energized by the reference voltage, thereby holding the latch member 50 in the latching position as shown against the bias of spring 58. In this position, the latch surface 54 engages the lug es of the plunger 39, thereby holding the plunger 39 against movement inwardly of the trip unit, such movement being urged by the end 49B of the spring 49 acting on the pin 47, which in turn acts on the plunger 39 at the end of the notch 43. If the voltage applied to the solenoid 35 decreases a predetermined amount, the plunger 56 will be allowed to be moved outwardly of the solenoid 35 by the action of the spring 58. In such a case, as the latch member 5t rotates clockwise as viewed, the latch surface 54 becomes disengaged from the lug 44, permitting the plunger 39 to be moved inwardly of the trip unit 21 by the action of the end 49B of the spring 49. The inward movement of the plunger 39 causes it to engage the trip member 27 of the trip unit 21, thereby initiating tripping action.

The parts are shown in the tripped or actuated condition in FIGURE 5, at the instant of releasing and before the contact arm 16 has moved to its off position.

As the arm 16 is moved toward off position by the action of the operating mechanism, the end portion 16A of the contact arm 16 engages the edge portion 46A of the link 46, and as the contact armv further moves to its full off position, it rotates the link 46 counterclockwise as viewed, thereby moving the pin 47 to the left as viewed. As this occurs, the portion 47B of the pin 47 picks up the left hand end of the notch 43, and moves the plunger 39 to its retracted or latched position. At the same time, the lower portion 47A of the pin 47 engages the extension 49B of the spring 49 and moves it counterclockwise. As the end 49B of the spring 49 moves counterclockwise in this manner, the right-angular bent portion 49B thereof engages the adjacent edge of the latch member 51 thereby moving the latch member 54 back to its initial position, carrying with it the plunger or actuator 56 which is returned to its initial position. If the reference voltage applied to the solenoid 35 is of proper value, the solenoid plunger or actuator 56 will then be held within the solenoid 35 and the plunger 39 will remain latched in its retracted position ready for a subsequent operation, and the breaker may then be turned on.

Any attempt to reclose the breaker before the voltage applied to solenoid 35 has returned to its sufiicient value causes the contact arm 16 to move away from the link 46. Thus the latch member is no longer restrained by the end 49B of the spring 49 and therefore the tension spring 58 is free to rotate the latch member 50 in a clockwise direction, releasing the plunger 39 once again to move to tripping position.

As the pin 47 moves back in a counterclockwise direction during the resetting operation, it first picks up the left hand end of the notch 43 of the plunger 39, and at the same ime moves he end 49B and the portion 49B of the spring 49 into engagement with the edge of the latch member 50. As the link member 46 continues further counterclockwise rotation, it will be observed that the plunger member 39 is being moved to the left or retracted position by the pin 47, and the latch member 50 is being moved counterclockwise toward its retracted position by the end 498' of the spring 49.

The latch member 50 cannot, of course, move to its full original position as shown in FIGURE 2, until the plunger member 3% has moved its full travel to the left so as to bring the lug 4d beyond the latch surface 5d of the latch Stl. The parts are preferably disposed and arranged so that the latch member 5@ has its counterclockwise rotation limited by engagement with the lug member 44 before the pin 47 reaches its full travel in a resetting direction. This also stops further travel of the end 49B of the spring 49B, and as the last portion of travel of the pin 4'7 takes place, it stresses the end portion 49B of the spring. When the plunger member 39 is moved far enough to the left, therefore, the lug member 44 clears the latch surface 54 and the latch is moved to its full original position with a snap action by the stored energy in the extended end portion 493 of the spring 49. This assures proper and complete latch overlap in the normal condition. By reason of the latch construction as described, the force required by the solenoid 35 to hold the plunger 39 against the substantial force of its biasing spring 49 is relatively small.

Physical Mounting 0f the Assembly it will be observed that the undervoltage trip device illustrated comprises a single self-contained unitary assembely comprising the plunger 39, latch member Sil and link 46 and associated springs and retaining elements. When such a device is being added to a breaker by the user therefore, there are no separate and loose parts to handle. Further, in accordance with the invention, the circuit breaker and the undervoltage trip device are both designed to cooperate in such a way that the trip device can be securely mounted within the insulating casing of the circuit breaker without the use of screws or other separate fastening elements.

In accordance with this aspect of the invention, the frame member 31 includes the bent-over portion 32, a struckout lug at), a notch portion 6-1 at the lower end of the portion 32, a generally hook-shaped end portion 33, an offset end portion 34A of the arm 34, and cooperating formations of the circuit breaker casing, as will now be described. As shown in FIGURE 3, in its mounted condition, the hooked portion 33 of the frame member 31 rests on an integral abutment 62 of the casing, which, as seen in this figure and in FIGURE 2, has vertically and horizontally extending wall portions defining a corner to receive and support the underside as well as the end of the portion 33 of the frame 31. The cover member 21B of the trip unit 21 is also provided with an aperture 63, see FIG. 6, which is adapted to receive the lug men ber 60 of the bent-over portion 32 of the frame 31. The outer surface of the trip unit cover 213 is also provided with an abutment 64 which is received in the notch er of the bent-over portion 32 to support the frame in a vertical direction.

The arm 34 is dimensioned so that the end portion 34A thereof rests against the partition wall 66 which defines one side wall of the pole chamber of the circuit breaker. See FIG. 3. The plunger member 3? extends through 6. an aperture 67 in the cover member 21B of the trip unit As shown particularly in FIGURES 2 and 3, the undervoltage trip assembly is tightly and securely received in the insulating base of the circuit breaker and is restrained from movement in any direction by means of the supporting points described.

For the purpose of facilitating the assembly of the undervoltage trip device in the relationship shown in FIG- URE 2, in which it is tightly wedged or received between the abutment 62 and the trip unit cover 21B, even though the plunger member 39 projects a substantial distance beyond the bent-over end portion 32, means is provided for retaining the parts of the device in a special pre-assembled condition, from which the parts are then moved as the device is being assembled. This aspect of the invention is illustrated in FIGURE 6. As shown, the plunger member 39 is provided with a notch 45. In order to assemble the device in a breaker, the plunger member 39 is manually pushed back to an extremely retracted position beyond the normal latched position shown in FIGURE 2, until the notch i5 is caught on the lower edge of the opening 42 in the bent-over portion 32 of the frame 31. With the parts in this condition, the assembly is placed in the circuit breaker in a preliminary position as shown in FIGURE 6, in which the front end 33 rests in the corner of the abutment 62, and the retaining lug as carried by the wall 32, rests against the wall 21B of the trip unit 21 just slightly above the opening 63 therein. With the parts in this position, a force, such as indicated by the letter F in FIGURE 6, is exerted at the rear portion of the frame 30 by suitable means, such as by hand, thereby wedging the frame 31 between the front wall of the trip unit 2113 and the vertical wall of the retaining formation 62, and permitting the lug dd to snap into the aperture 63. In addition to this action, as the frame 31 is pushed downwardly into position, the right hand end of the plunger 39 is moved relatively upwardly in slot 42 of the bent-over portion 32, so that when the parts are in the final inserted position, as shown for example in FIGURE 2, the plunger 39 snaps out of the latched engagement with the lower edge of the slot 42 and projects further to the right in its initial position as shown in FlG- URE 2. This position being determined by the engagement of the lug 44 with the latch surface 54.

Remote Trip Form In accordance with another aspect of the invention, the parts may be readily adapted to operate as a remote trip device, rather than an undervoltage trip device. In the undervoltage trip device, the parts are normally biased toward tripping condition but are restrained from causing tripping by the solenoid which is normally energized. A failure of voltage in the solenoid therefore permits tripping to occur by spring action (spring 53). In the remote-trip device, the parts are normally in a latched condition, and are moved temporarily to a tripped condition by means of the solenoid plunger action. This form of the invention is illustrated in FIGURE 7, and has parts corresponding to those previously described with the exception that the solenoid 35 is replaced by a solenoid 135, in which the plunger 156 is normally biased to an unattracted or outer position to the left, and operates a push rod 156' connected to the latch member 56 In addition, the tension spring 58 is removed from the hole 5% in the lower part of the latch 50 and is reengaged in a second hole 159 above the pivot 48A of the latch member. The tension spring 58, in this form, therefore tends to hold the latch member Sit in its latched condition. When the solenoid is energized, the plunger 1% is pulled into the coil, forcing the push rod 156 to the right and rotating the latch member 50 clockwise against the pull of the tension spring 53. This releases the plunger member 39 to be moved to tripped position in the same manner as previously described. As the contact arm 16 moves upwardly toward open position, the edge portion 16A engages the link 46 and causes resetting of the latch member 50, and movement of the plunger 156 to the original position in a manner similar to that described in connection with the form of FIGURE 2.

For the purpose of deenergizing the solenoid 135 when the parts have moved to open circuit position, a cut off switch 70 is provided, which is also mounted on the frame member 31 by suitable means such as by screws or rivets 71. An elongated fiat resilient actuator '72 is provided which is rigidly attached to the arm 34 by suitable means such as by welding, and at its intermediate portion engages the actuator 73 of the switch 70. When the contact arm 16 moves clockwise from the position shown in FIGURE 7 to its open circuit condition, it engages the end portion of the actuator '72 and causes operation of the switch 70 to interrupt the circuit to the solenoid 135.

It will be observed that there is provided in accordance with the invention an undervoltage trip device which is compact and effective and which can be readily mounted in a molded case circuit breaker by simple push-in action without the use of separate fastening means.

It will also be observed that there is provided an undervoltage trip device which can be readily converted to a shunt-trip device.

While the invention has been disclosed in only two particular embodiments, it will be readily apparent that many modifications thereof may be made, and it is therefore intended by the appended claims to cover all such modifications as fall within the true scope and spirit of the invention.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. For use with an electric circuit breaker including at least one pair of relatively movable contacts, operating mechanism for operating said movable contacts between open and closed circuit positions and trip means including a trip member movable to cause automatic opening of said contacts, an automatic tripping device comprising:

(a) a support,

(b) a solenoid supported on said support and including a reciprocally operable actuator,

(c) a tripping plunger slidably supported on said support,

(d) first biasing means carried by said support and biasing said tripping plunger in a tripping direction to engage and operate said circuit breaker trip member,

(e) a latch member pivotally supported on said support and including a portion releasably holding said tripping plunger,

(f) means connecting said latch member to said solenoid actuator,

(g) second biasing means carried by said support and biasing said latch member in releasing direction,

(11) said solenoid when energized serving to hold said solenoid actuator in retracted position to retain said latch member in latching position and,

(i) a resetting lever pivotally supported on said support and including means for engaging said tripping plunger to return said tripping plunger to latched position when said resetting lever is moved in a predetermined resetting direction.

2. For use with an electric circuit breaker including at least one pair of relatively movable contacts and a trip member movable to cause automatic opening of said contacts, a tripping device comprising:

(a) a generally planar support,

(b) an electric solenoid mounted on said support, and

including a reciprocally operable actuator,

(c) a tripping plunger slidably mounted on said support,

(d) biasing means biasing said tripping plunger in tripping direction,

(e) a latch member pivotally supported on said support and including a latch portion releasably engaging said tripping plunger,

(1) means biasing said latch member in releasing direction,

(g) means connecting said latch member to said solenoid actuator whereby said latch member is held in latched position against the bias of said latch member biasing means by said solenoid member when energized,

(h) an operating lever pivotally supported on said support and having an engagement with said tripping plunger,

(i) said tripping plunger biasing means including a portion engaging said operating lever to urge said operating lever for rotation in a first direction into engagement with said tripping plunger and to urge said tripping plunger in tripping direction,

(j) said operating lever, when rotated in a direction opposite to said first direction, engaging said tripping plunger to move said tripping plunger to relatched position and engaging said tripping plunger biasing means to move said tripping plunger biasing means into engagement with said latch member, whereby to resiliently hold said latch member in latching position and to simultaneously move said tripping plunger back toward relatched position.

3. For use with an electric circuit breaker including a molded insulating casing, at least one pair of relatively movable contacts supported in said casing, and trip means including a member releasably movable to cause automatic opening of said contacts, electrically operable trip means comprising:

(a) a generally planar support,

(b) an electric solenoid mounted on said support, and

including a reciprocally operable actuator,

(c) a tripping plunger slidably carried by said support,

(d) an operating lever pivotally mounted on said support, said operating lever having a portion directly engageable with said tripping plunger to move said plunger in both tripping and resetting directions respectively,

(e) biasing means biasing said operating lever for movement in a direction to cause tripping movement of said tripping plunger,

(1) a latch lever pivotally supported on said support, said latch lever being operatively connected to said solenoid actuator and having a releasable latched engagement with said tripping plunger, whereby said solenoid when energized holds said latch lever in latching position to prevent movement of said tripping plunger by said biasing means,

(g) said biasing means including a resilient portion extending between said operating lever and said latch lever whereby movement of said operating lever in said resetting direction causes said resilient portion to engage said latch lever while said operating lever is moving said tripping plunger in reset direction to maintain a bias on said latch lever in the latching direction until said tripping plunger is moved to reset position.

4. An electric circuit breaker comprising:

(a) a generally rectangular insulating main casing,

(b) at least one pair of relatively separable contacts in said casing,

(c) operating mechanism for operating said contacts between open and closed circuit position,

(d) trip means including a separate insulating enclosure within said main casing and a member movably supported in said separate enclosure and movable to cause automatic opening of said contacts,

(e) electrically operable tripping means in said casing comprising a frame member of flat sheet metallic material,

(f) an opening in said trip unit enclosure,

(g) a tripping plunger slidably supported on said frame member and extending into said opening in said trip unit enclosure,

([1) electrically operable means carried by said frame member for causing tripping movement of said tripping plunger,

(i) means retaining said frame member in said insulating casing comprising supporting formations integral with said trip unit enclosure and with said main casing respectively whereby said frame member is capable of being assembled in said circuit breaker by push-in type assembly to a position in which it is retained by engagement with said formations carried by said trip unit enclosure and said main casing respectively without the use of separate fastening elements.

5. An electric circuit breaker comprising:

(a) a generally rectangular insulating casing,

(12) a plurality of spaced wall portions defining a plurality of pole chambers in said insulating casing,

(c) at least one pair of relatively separable contacts supported in each of said pole chambers,

(d) operating mechanism supported in said casing for operating all of said pairs of contacts between open and closed circuit positions, and including a member releasable to cause automatic opening of said contacts,

(e) current responsive means normally restraining said releasable member and causing release thereof upon the occurrence of predetermined current conditions comprising a separate trip unit enclosure supported within said casing and extending across all of said pole chambers,

(f) said current responsive means including a trip member within said trip unit enclosure movable to cause tripping of said circuit breaker,

(g) an electrically Operable tripping device supported in one of said pole chambers outside of said trip unit enclosure,

(11) said tripping device including a sheet metal supporting frame having a main generally planar portion disposed in said chamber in parallel relation to a first one of said wall portions and a pair of bent-over portions disposed at opposite ends respectively of said generally planar portion, one of said bent-over portions including an integral projection received within a first aperture in said trip unit enclosure, the other of said bent-over portions including a portion extending completely across said pole chamber and providing a support point for said supporting frame on a wall portion of said pole chamber opposite from said first wall portion,

(i) a second aperture in said trip unit enclosure, and

(j) a tripping plunger carried by said supporting frame and disposed and arranged to move within said second aperture upon actuation of said tripping device to engage and actuate said trip member Within said trip unit casing.

6. For use with an electric circuit breaker having a main molded insulating casing and a trip unit enclosure supported within said main casing, said trip unit enclosure including an opening therein to receive a trip actuating plunger, an electrically operable tripping device comprismg:

(a) a supporting frame,

(b) a tripping plunger carried by said supporting frame,

(c) first latch means carried by said supporting frame for normally restraining said tripping plunger in a first latched position,

(d) electric solenoid means carried by said supporting frame and disposed and arranged to cause release of said tripping plunger from said first latched position upon the occurrence of predetermined electrical conditions for movement to a released position to actuate said trip unit,

(e) second latch means carried by said supporting frame,

(1) said tripping plunger being movable to a second latched position in which it is engaged and held by said second latch means, said second latched position further withdrawn from said released position than said first latched position to facilitate assembly of said tripping device in said circuit breaker.

7. An electric circuit breaker comprising:

(a) a main molded insulating casing,

(b) a trip unit having a separate insulating enclosure supported in said main casing, a trip member supported in said trip unit enclosure and movable to cause automatic opening of said circuit breaker,

(c) an opening in said trip unit enclosure affording ac cess to said trip member,

((1') an auxiliary tripping device mounted in a predetermined position in said main casing outside of said trip unit enclosure, said auxiliary tripping device comprising a supporting frame,

(e) a tripping plunger carried by said supporting frame,

(1) first latch means carried by said supporting frame for normally restraining said tripping plunger in a first latched position,

(g) electric solenoid means carried by said supporting frame and including an actuator connected to said first latch means to cause release of said tripping plunger from said first latch means upon the occurrence of predetermined electrical conditions for movement to a released position to engage and actuate said trip member in said trip unit enclosure through said access opening,

(h) second latch means carried by said supporting frame for restraining said tripping plunger in a second latched position,

(i) said tripping plunger when in said second latched position being further withdrawn from said released position than when in said first latched position to facilitate assembly of said tripping device in said circuit breaker,

(j) said tripping plunger having a portion engageable with a portion of said trip unit enclosure defining said access opening and being released thereby from said second latch means as said tripping device is mounted in said predetermined position, whereby said tripping plunger may be placed in said second latched position prior to installation of said tripping device in said circuit breaker and released therefrom as said trip device is installed in said circuit breaker.

References Cited by the Examiner UNITED STATES PATENTS 65 BERNARD A. GILHEANY, Primary Examiner. 

1. FOR USE WITH AN ELECTRIC CIRCUIT BREAKER INCLUDING AT LEAST ONE PAIR OF RELATIVELY MOVABLE CONTACTS, OPERATING MECHANISM FOR OPERATING SAID MOVABLE CONTACTS BETWEEN OPEN AND CLOSED CIRCUIT POSITIONS AND TRIP MEANS INCLUDING A TRIP MEMBER MOVABLE TO CAUSE AUTOMATIC OPENING OF SAID CONTACTS, AN AUTOMATIC TRIPPING DEVICE COMPRISING: (A) A SUPPORT, (B) A SOLENOID SUPPORTED ON SAID SUPPORT AND INCLUDING A RECIPROCALLY OPERABLE ACTUATOR, (C) A TRIPPING PLUNGER SLIDABLY SUPPORTED ON SAID SUPPORT, (D) FIRST BIASING MEANS CARRIED BY SAID SUPPORT AND BIASING SAID TRIPPING PLUNGER IN A TRIPPING DIRECTION TO ENGAGE AND OPERATE SAID CIRCUIT BREAKER TRIP MEMBER, (E) A LATCH MEMBER PIVOTALLY SUPPORTED ON SAID SUPPORT AND INCLUDING A PORTION RELEASABLY HOLDING SAID TRIPPING PLUNGER, (F) MEANS CONNECTING SAID LATCH MEMBER TO SAID SOLENOID ACTUATOR, (G) SECOND BIASING MEANS CARRIED BY SAID SUPPORT AND BIASING SAID LATCH MEMBER IN RELEASING DIRECTION, (H) SAID SOLENOID WHEN ENERGIZED SERVING TO HOLD SAID SOLENOID ACTUATOR IN RETRACTED POSITION TO RETAIN SAID LATCH MEMBER IN LATCHING POSITION AND, (I) A RESETTING LEVER PIVOTALLY SUPPORTED ON SAID SUPPORT AND INCLUDING MEANS FOR ENGAGING SAID TRIPPING PLUNGER TO RETURN SAID TRIPPING PLUNGER TO LATCHED POSITION WHEN SAID RESETTING LEVER IS MOVED IN A PREDETERMINED RESETTING DIRECTION. 